Repeating fuse



Nov. 3, 1936. T. F. JOHNSON REPEATING FUSE Filed March 4, 1935 6Sheets-Sheet l amen M T1 nfafinJan Gum 4 Nov. 3, 1936. I T. F. JOHNSON2,059,796

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T. F. JOHNSON REPEATING FUSE 6 Sheets-Sheet 3 Filed March 4', 1935dual/MA Nov. 3, 1936. T. F. JOHNSON Y 2,059,796

REPEATING FUSE Filed March 4, 1935 6 Sheets-Sheet 4 mum" l l l QwmmmmmwmNov 3, 1936. T. F. JOHNSON REPEATING FUSE Filed March 4, 1955' 6Sheets-Sheet 5 Show;

T. F. JOHNSON REPEATING FUSE Nov. 3, 1936.

Filed March 4, 1955 6 Sheets-Sheet 6 TE zfa/gnson Patented Nov. 3, 1936BEPEATING FUSE Tomlinson Fort Johnson, Atlanta, Ga. Application March 4,1935, Serial No. 9,340

16 Claims.

This invention relates to repeating fuses or automatic fuse-reclosersfor high tension electric circuits and, among other objects, aims toprovide improved and greatly simplified mechanism having means toreplace a series of fuses successively after they are blown due to anoverload which generally results from some tran-- sient condition, suchas a lightning flash-over or a temporary short circuit. Another aim ofthe invention is to provide simple mechanism whereby blown fuse elementsmay be quickly replaced and again put in service. Also a feature of theinvention is the provision of adjustable time-delay mechanism wherebythe reclosing 1s fuse will serve as a delayed action switch having allof the advantages of the more expensive reclosing oil circuit-breakers.

This application is a continuation-in-part of my copending application,Ser. No. 662,143 filed 20 March 22, 1933. I

Other aims and advantages of the invention will appear in thespecification, when considered in connection with the accompanyingdrawings, wherein: 25 Fig. 1 is a side elevation of a reclosing .fuse assembly embodying the invention;

Fig. 2 is a front elevation of the. fuse'mechanism shown in Fig. 1;

Fig. 3 is a lower end view or bottom plan of 30 the mechanism; 5

Figs. 4, 5 and 6 are sectional views taken on the lines 4-4, 5-5 and6-8, respectively, of Fig. '2;

Figs. 7, 8, 9 and 10 are elevations of latch mem- 35 bers for the fusesockets;

Fig. 11 is a sectional view partly in elevation of the preferred formoffuse sockets;

Fig. 12 is a central sectional view of one of the fuse units mounted inits socket; 40 Fig. 13' is a side elevation of one of the fuse unitsready to be inserted in one of the sockets;

Fig. 14 is a lower end view of the unit shown in Fig. 13;

Fig. 15 is afragmentaryelevation showing the position of the partsafter, a fuse is blown;

Fig. 16 is a fragmentary sectional view taken on the line Iii-48 of Fig.2; p

Fig. 17 is a similar sectional view showing the fuse unit in itscircuit-closing position;

Fig. 18 is a central sectional view of a dashpot on an enlarged scale;

Fig. 19 is a sectional view taken on the line I9-l9 of Fig. 18; and 55Fig. 20 is a view similar to Fig. 3' but showing two of the fuse unitshaving time delay mechanism applied thereto.

' Referring particularly to the drawings. the r:- closing fuse mechanismis shown as being mounted on insulators l0 and H which are secured to asuitable vertical support 12 (Fig. 2), which is usually in the form of astructural channel member. The automatic mechanism is carried by a metalbracket I3 bolted to the insulator Ill and expulsion units It, I 5 and16 are pivot- 10 ally mounted on this bracket so as to be swungsuccessively into circuit-closing positions, engaging jaws il mounted ona bracket l8 which is bolted to the other insulator II. The brackets 13and 18 are made of bronze or other suitable conducting metal and eachhas a terminal arm l9 adapted to be connected to one of the phases of atransmission line.

Referring to Figs. 1, 2 and 3, the bracket I3 is shown as having fourupstanding gears 20, 2!, 2o 22 and 23 between acfiacent pairs of whichthree cylindrical open ended metal sockets 24 are pivotally mounted toreceive the respective fuse units l4, l5 and It. It is to be understoodthat any number of fuse units may be employed. In this instance, each ofthe sockets has a pair of integrally opposed trunnions 25 and alinedholes are drilled through these trunnions to receive hinge pins 28forced into openings in the two intermediate ears 2! and 22 and shortpins 21 flush 30 with the outer faces of the outside cars 20 and 23. Thearrangement is such that the sockets are mounted for independentswinging movement. Furthermore, the sockets can be assembled insuccession between the brackets, and each of the sockets has a flaredend within which a metal ferrule 28 on each of the fuse units is guidedendwise. Metal ferrules 29 are also secured to the free ends of thetubes which are made of insulating material to contact with the laws 11.

The ferrules 28 are shown as having surface contact with the sockets. InFigs. 11 and 12, the

sockets have openings at one side ,to receive spring tongues 30projecting into the sockets and making good electrical contact with thelower portions of the ferrules when they are pushed home. Furthermore,the sockets are electrically connected to the base of the bracket 13 bymeans of flexible conductors or cables 3| conveniently secured to thesockets by screws 32 used to secure the tongues 30.

In this example, the fuse units are normally biased, toward. theirclosed positions by means of tension springs 33 (Figs. 1, 3, 16 and 17),each connected at one end to a notched arm 34integral with the upper endof one of the sockets and, at its other end, to an adjustable pivotedarm 35. The arms 35 are journaled on shafts 36, 31 and 38 whichare inturn journaled in the ears 20 to 23 inclusive and another set of shortcars 39, 40 and 4| best shown in Figs. 2 and 3. The arrangement is suchthat the fuse units can be tensioned in cocked position at an angle ofabout to the vertical and they are adapted to be latched or locked inthis position by means of latch arms 42 secured to the respective shafts36 to 38 inclusive adjacent to the arms 35 and each carrying a roller 43adapted to engage integral brackets 44 on the fuse sockets shown asextending at approximately right angles to their axes. The brackets 44are flanged at their free ends and have screws 45 to act as adjustablestops for the rollers when the latch arms are swung into their cockedpositions, as shown in Fig. 16.

The latch arms 42 and the spring arms 35 are mounted side by side oneach of their shafts and the spring arms are adapted to be adjustedrelative to the latch arms so as to displace the spring connections fromalinement with the shaft and transmit movement to the latches. Also, thearms may be adjusted to vary the tension of the springs. For thispurpose, each arm 35 has an ear carrying a. set screw 46 engaging alateral car 41 on the latch arm 42. Also, each spring arm is adjustablysecured to its latch arm by a machine screw 48 in the latch arm passingthrough an elongated slot in a lateral ear on the spring arm 49. Theposition of the arms and connections are such that the act of swingingeach fuse unit to its cocked position causes the springs to impart fullcocking movement to the latch arms so that they are lockedautomatically. In the cocked position the latch arms act as the stifflegs which are approximately parallel with the sockets and normal to thefaces of the brackets 44. Incidentally, the sockets are shown as beinglimited in their swinging movement to cocked position by means oflateral lugs 50 on the respcctive sockets adapted to engage the upperedges of the adjacent brackets.

The mechanism is designed to trip the fuses automatically in sequence orin succession when the fuse elements are blown. For this purpose, thelatch members are adapted to be tripped by means of triggers which areoperated incident to the blowing of. the fuses. Referring to Figs. 1, 2,and 3, the first fuse unit I4 is adapted to be released or tripped bymeans of a manually operated trip arm 5i mounted on the first latchshaft, 38 outside 'of the bracket 20. This fuse unit is shown in itscircuit closing or activeposition. On the second latch shaft I! there isshown a trigger 52 having an offset portion or finger in line with theopen end of the first fuse socket. The arrangement is such that when thetrigger I2 is moved downwardly, it trips the second fuse latch.Likewise, there is a second trigger 52, identical with the first one, onthe third latch shaft 38 and it is arranged to be tripped when thesecond fuse unit is blown so as to release the third fuse unit. A thirdtrigger I2 is shown as being mounted adjacent to the third fuse andfixed on a fourth trigger shaft 53 which projects through and beyond theoutside bracket 23. This shaft carries an arm 54 and the opposite shaft38 carries a similar arm 55 to the outer ends of which a bar 56 isconnected. nu.- arrsngement is such that when the third fuse unit I6 isblown, the two arms and the bar will trip the latch for the first fuse,in the event that it was left in cocked position. By this arrangement,any blown fuses may be replaced, while any good one is connected andthey will be tripped in continuous sequence.

Referring now to the automatic mechanism for tripping the triggers, thefuse units are arranged to expel their ruptured fuse elements throughthe rear or lower open ends of the fuse sockets and thereby effect therelease of the triggers. Referring to Fig. 12, the fuse tubes each carrya tension fuse wire 57 having a fusible link soldered at its upper endto a member 58. These fuses are of a well known type.

The upper ends of the fuse tubes are open and the ferrules 29 extendbeyond them. Metal disks 59 are inserted in the open ends of theferrules against the ends of the tubes and carry the usual flangedwashers or adapters Bil providing contact members for rounded heads BIon the upper ends of the fuse members 58. The ends of the ferrules areshown as being screwthreaded and closed by plugs 62 of good conductingmaterial adapted to be tightly screwed against the heads BI and makegood electrical contact therewith. Thus, the fuse links are easilyremovable and replaceable, the ends of the plugs having screw driverslots for that purpose.

The fuse wires 51 project through the lower open ends of the lowerferrules 28 and are adapted to be connected to spring tensioned memberswhich, when released, strike the triggers. In this example, bracketmembers 53 are shown as being clamped on the ferrules 28 near theirupper ends and project at an angle to the axes of the tubes. The outerfree ends of the bracket members have spaced hinge ears 64 to which areconnected knee-jointed hammers each comprising an arm 65 secured on apin Bl projecting through the hinge cars 64 and a. hammer member 61pivotally connected between cars 68 on the arm 65 and presenting o. camgripping surface 69 cooperating with a gripping face 10 between the ears68. The hammer members are shown as being notched or bifurcated at H toreceive the fuse wires which are threaded through the notches andbetween the cam surface 69 and the gripping surface ID, the hammerhaving a smooth central guiding groove to prevent displacement of andsharp bends in the wire. Also, the end of each hammer member has abulb-shaped enlargement 12 adapted to guide it into the open end of theferrule 28.

Mounted on the hinge pin 88 is a coil spring II normally urging thehammer to swing downwardly so as to engage a trigger and knock it to itslatch releasing position. To make good electrical contact between thebracket arms and the hammer members, flexible wires 14 are shown asconnecting them. Furthermore, the spring-urged arm of the hammer islimited in its swinging movement by means of a pair of stop shoulders 15machine adjacent to the cars 84 to engage the outer edges of the earswhen the hammer is swung through approximately as best shown in Fig. 15.Moreover, the swinging movement of the hammer member 61 with respect tothe arm or leg 05 is limited by means of a. pair of lateral stop pins 18adapted to engage the edges of the ears 68. The arrangement is such thatwhen the hammer arms are swung into a position so that the forked endsof the hammers close the lower ends of the ferrules and the two arms areswung upwardly at their joint. from the position shown in Figs. 12and13, the free end of the fuse wires may be inserted between thegripping faces 69 and 10. Then, when the arms are released the springtension will cause them to swing into the position shown in Figs. 12 and13, not only to grip and hold the end of the fuse wire but also to placeit under a slight tension. The tension on the wire is determined by thestrength of the coil spring I3 and the length of the knee-jointedhammer.

As soon as a fuse link blows, the hammer is released and strikes thetrigger finger below it. Then, it swings to the fuse blown positionshown in Fig. 15. The power of the trigger hammers is somewhat augmentedby gravity and by an explosion within the fuse tube causing the gasformed to escape through the open end of the tube. Hence, the springs donot need to be of very great strength to insure positive action. Due tothe swinging action of the hammer, the knee-joint is broken and theblown fuse wire is released from its gripping engagement so that it isthrown outwardlyv and downwardly to the ground. Furthermore, a linemancan instantly determine which fuses have been blown by the positions ofthe hammers as shown in Fig. 15.

Referring toFigs. 3, 6, 11 andlZ, each of the fuse sockets is shown ashaving a longitudinal slot H in its front wall and the hammer arms 61present narrow neck portions 18 insertable in said slots to permit theunits to be pushed home in the sockets. Also, the brackets 63 haveextensions 19 presenting rounded lower edges adapted to engage and. fitsnugly into the upper end portions of the slots so as to preventrotation of the fuse unitsand keep the hammers in line with theirrespective triggers. Moreover, the clamping members of the bracketsserve as stops to limit the endwise movement of the fuse tubes when theyare inserted in the sockets. The reduced neck portions 18 on the hammersare somewhat narrower than the width of the slots IT in the sockets sothat when the fuse tubesare centered in the sockets by the bracketprojections 18, the hammers are free to swing downwardly without bindingin the slots atthe lower ends of the sockets.

To enable fuse replacers of this type to serve the same purpose, asreclosing oil circuit breakers, it is necessary to delay the reclosingoperation of one or more of the fuse units after a fuse is blown. InFigs. 1, 2 and 3, the fuse assembly is shown as being provided with onetime-delayed fuse unit. In this instance, the third fuse unit I6is.connected to a dashpot having a cylinder 80 pivotally connected bytrunnions 8! to bracket 82 which is bolted to the outside of the ear Z3and has a piston rod 33 adjustably connected to a lateral arm or pin 84on the upper end portion of the third socket by means of an extension85' having an elongated slot 86 engaging the pin. The dashpot, which isshown in detail in Figs. 18 and 19, is of the leakage and by-pass typepreferably being filled with oil and having a cup-shaped piston 81presenting openings 88 closed by a check valve 89 limited in its openingmovement by a pin 90. The cylinder 88 is filled with oil through fillingplugs 8| alined with bypass openings 92 and 93 which communicatewith aby-pass 94. The upper end of the dashpot cylinder isshown as beingclosed by a head .95-

which is preferably secured in the end of the,

cylinder by brazing or welding. This head carcompressed by a packinggland 81.

ries a stufllng box, 96 through which the piston rod extends and thepacking is adapted to be Theupper end of the piston rod is screwthreaded into the extension 85 and secured by means of a lock nut 98. Acompression spring 88 surrounds the piston rod between the packing glandand the lock. nut normally to urge the piston upwardly and 1 keep theinnermost end of the slot 86 in the extension in engagement with the pin84. The construction and arrangement are such that the piston isautomatically moved to the cocked position or the position'shown in Fig.18 when the third fuse unit is swung to its cocked position.

The piston serves to delay the release of the fuse unit due to thetrapped oil in the outer or lower end of the cylinder below thecup-shaped piston. After the latch for the third fuse is released andthe unit is ready to close, the pin 84 moves freely in the slot 86 untilit contacts the outer end and imparts a jerk to the piston. This freeinitial movement of the fuse unit and socket prevents the tripped latch42 from returning to its stiff -leg or looking position which otherwisewould prevent the fuse from closing. The bracket faces are slightlyoffset (Fig. 16) to provide ample clearance for the rollers 43 when theyare tripped. However, oil must leak slowly past the piston with thecheck valve closed until the lower end of the piston uncovers theby-pass port 93. As soon as this happens, oil by-passes very rapidlythrough the ports 92 and 93 around the piston and permits rapid closingof the fuse unit. The quick movement is necessary to prevent theswitches from being burned off as they approach the jaws. Now, the timedelay can be adjusted by varying the distance which the piston 81overlaps the lowermost edge of the port 83; This is done'by thescrew-threaded connection between the extension 85 and the piston rod83. By extending the effective length of the piston rod from the cookedposition of the pin 84, it may be sdadjusted that the-piston will bepositioned at the ex-.

treme bottom end of the cylinder. This will givea maximumtime delay. Onthe contrary, the effective length of the piston rod may be shortened toreduce the amount of overlap of the piston or to change its position sothat it just covers the port 93 and thereby reduces the time delay to aminimum. Incidentally, whenthe piston is adjusted as shown, thecompression spring 98 supports its weight and prevents it from fallingin the cylinder to a diiferent time delaying position from the positionfor which it is adjusted. In practice, it is desirable to vary the timedelay from approximately a half second to 2 minutes.

When only one dashpot is used on the third fuse unit as shown, it isdesirable that thisfuse unit shall always be thelast one to close.Without a dashpot, the sequence of operation is immaterial because anytwo units may be left cooked and the other unit in its circuit closingposition. With the dashpot, the first fuse unit is always left closed asshown in Figs. 2 and 3. When the first fuse unit blows, the middle onewill be tripped and try to restore the servicepracticallyinstantaneously. If the middle unit fails to restore the service and isblown due to a continued abnormal condition, the third fuse will betripped and delayed in its closing for a predetermined time intended topermit any ordinary transient condition to clear up.

The blown fuse units are adapted to be manilally opened by usingordinary switch hooks engaged in hook eyes lllllconveniently clamped onthe lowernortions'of theupper ferrules 28 as best shown in Fig. 1. Thesehook eyes slightly increase the momentum of the fuse units when they areforcibly closed by the tension springs 33. Hence, the switch jaws areprovided with comblned spring shock absorbers and contact mem bers llH.These springs are conveniently made of phosphor bronze strips bentU-shaped with their free ends projecting toward the hinged ends of thefuse units. As shown in Figs. 4 and 5, the jaws have relatively movablejaw elements I02 on spring brackets I03 so that they automaticallyadjust themselves to contact with the sides of the fuse ferrules 29 andthe spring pressure of the jaws may be varied by means of bolts I04passing through the spring brackets. These incidental features insuregood electrical contact between the fuse units and the laws.

It will be understood that the fuse elements may easily be replaced bybodily removing each blown fuse unit from its fuse socket with anordinary switch hook and taking it down to a platform or to the ground.A lineman may substitute new units for ones having blown fuses and takethe old ones to a shop for inspection and replacement of the fuseelements. The units are inter changeable because they are identical andthey may be inserted in the sockets also by using the switch hook sothat a lineman does not need to come in physical contact even with theblown assembled units.

It is sometimes desirable to use two timedelayed fuses in a reclosingdevice of this character. Thisis especially true if the line is sub-Jected to more or less frequent lightning flashovers or if theinspections are infrequent. Obviously, two time delayed closures willinsure two restorations of service if the abnormal conditions do notpersist too long. In the embodiment of the invention shown in Fig. 20,two dashpots are shown as being provided for the two outside fuse units.These two units are selected because it is most convenient to mount thedashpots adjacent to them. A dashpot is not necessary for the fuse whichis left in its active position. In this case, the middle fuse is placedin service and the two outside fuses are left cocked. Herein lies one ofthe advantages of the continuous sequential operation of the fuseunits.The same mecha-- nism is employed for operating fuses either with orwithout dashpots and this enables 'it to be standardized. It will beunderstood that when the middle fuse unit shown in Fig. 20 blows, theright hand fuse unit will be tripped and. when the right hand fuse unitblows, the left hand unit will be tripped by means of the arms 55 andcross bar I. In this case, the two right hand triggers 52 are the activeones, the left hand trigger having been swung to its tripped position torelease the middle fuse and put it in service. In all other respects,the construction and operation of the mechanism shown in Fig. 20 isidentical with that hereinbefore described. This type of mechanism isbest suited for displacing the far more expensive automatic, reclosingoil circuit breakers.

Prom theforegoing description, it will be seen that the mechanism isrelatively simple in its construction and design. It is very rugged andhas no delicate mechanical parts which require quick replacement orexpensive maintenance;

Inspection and replacement of the fuse elements may be made by ordinarylinemen'and there is no possibility of making a mistake as to the fuseunits which have been blown. Service tests have shown that the fusereplacers are absolutely dependable in operation. In fact, they havebeen adopted as standard equipment on some high tension electricalsystems.

Obviously, the present invention is not restricted to the particularembodiment thereof herein shown and described. Moreover, it is notindispensable that all the features of the invention be used conjointly,since they may be employed advantageously in various combinations andsub-combinations.

What is claimed is:

1. In a fuse replacer of the character described, a plurality of pivotedexpulsion fuse units each arranged to expel its fuse elements throughits pivoted end; means normally biasing said fuse units to their circuitclosing position; means to latch the inactive fuses in cocked positionready to be closed as the active fuses are blown in succession; triggersconnected to operate each of said latch means in the order ofsuccession; and spring urged pivoted striker members for said triggersassembled on the fuse units and connected to be released by the fuseswhen they are blown.

2. An automaticfuse changer for electric circuits comprising, incombination, a plurality of expulsion fuse units; open ended cylindricalsockets each pivoted at one end carrying said fuse units; tensionsprings connected to the free ends of said sockets normally to swingsaid fuse units to circuit closing position; latch means to hold saidsockets in cocked position; and triggers connected to the respectivelatches lying immediately behind the rear open ends of adjacent fusesockets when in closed position and each adapted to be tripped by thenext adjacent fuse.

3. In a repeating fuse of the character described, a pair of spacedinsulators; a bracket mounted on one of said insulators having aplurallty of spaced cars at right angles thereto; a plurality ofsubstantially cylindrical fuse sockets each having a flared end andpivotally mounted at its opposite end between pairs of said ears;expulsion fuses having their contact sleeves removably inserted in theflared ends of said sockets and adapted to project the expelled elementsthrough the rear ends of said sockets; tension springs connected to theflared ends of said sockets and normally urging them to circuit closingposition; latch mechanism connected to hold said sockets in cockedposition; fuse-operated tripping mechanism for the latches of successivefuses arranged to release the latch of each succeeding adjacent fuse asthe fuses are blown and their fuse elements are expelled tive fuseunits.

4.'In an automatic fuse replacing mechanism of the class described, apair of spaced insulators a bracket mounted on one of said insulatorsand having a plurality of integral ears at right angles thereto; aplurality of open substantially cylindrical fuse sockets each-pivotallymounted adjacent to one end on said ears and having springs connected totheir free ends normally to urge them to circuit closing position; aplurality of expulsion fuse units mounted in said sockets and havingtensioned fuse elements arranged to discharge through the rear ends ofsaid sockets; latch and trip mechanism mounted on said bracket connectedto hold the successive fuses in cocked position and adapted to beoperated by the blown fuses to release the fuse sockets in succession;and a bracket carrying adjacent jaws said sockets andadapted to projectthe fuse elements through the rear ends of said sockets; a secondbracket carrying a plurality of jaws for said fuse units; tension coilsprings normally 4 urging said fuse units to their circuit closingposition and connected to said sockets; a separate rotatable shaftadjacent to each of said sockets carrying a locking latch and an offsettrigger, said offset trigger being positioned directly behind anadjacent socket to be operated by the fuse therein as it is blown; andan arm oneach of said shafts also connected to one of said springs andarranged to restore the latch and the trigger automatically to theircocked position when the corresponding fuse unit is swung to its circuitopening position.

6. In an automatic fuse replacer of the character described, a brackethaving a conductor terminal; a plurality of spaced parallel ears on thebracket; a plurality of cylindrical open ended sockets each havinghollow lateral trunnions adjacent to one and inserted in the respectivespaces between the ears; pivot pins pressed into the ears through thetrunnions; tension springs connected to the free ends of the socketsnormally biasing them to swing to their circuit closing positions;expulsion fuse elements each inserted at one end into said sockets;separate shafts journaled on said bracket, one for each fuse unit; alatch arm on each shaft toengage a socket and hold it in cockedposition;triggers also fixed on each of said shafts adapted to trip the latch foran adjacent fuse unit, one trigger being manually operable to trip thefirst fuse unit and the other triggers being operable automatically asthe preceding fuse units are blown whereby the fuses are closed insuccession; and a bracket carrying contact clips for the respectivefuses.

'7. In a fuse replacer of the character described, a bracket carrying aplurality of pivoted cylindrical sockets each having a flared mouth; aplurality of expulsion fuse units removably inserted through the flaredmouths of said sockets and adapted to project the fuse elements throughthe rear ends of said sockets; a second bracket carrying a plurality ofadjacent contact jaws for said fuse units; springs normally urging saidfuse units to their circuit closing position and connected to saidsockets; a separate shaft adjacent to each of said sockets carrying alocking latch and an offset trigger, said offset. trigger being arrangeddirectly behind the rear end of an adjacent socket to be operated by thefuse therein as it is blown; and an arm on each of said shafts alsoconnected to one of said springs and arranged automatically to restorethe latch and the trigger to their cocked position when thecorresponding fuse'is moved to' its circuit opening position.

8.111 a fuse replacer of the character described, a metal bracket; aplurality of open ended, cylindrical sockets each pivoted at one end tosaid bracket; fuseunits removably and interchangeably mounted in saidsockets; a plurality of jaws for said fuse units; means normally biasingsaid sockets to swing said fuse units to their circuit closingpositions; latch means for holding said sockets in cocked position withthe cars thereon; three adjacent cylindrical sockets open at both endsandpivotally mounted at one end between pairs of said ears; a tubularfuse unit removably mounted in each of said sockets; a plurality ofadjacent jaws for the fuse units; means-normally biasing said sockets toswing the fuse units to their circuit closing position; latchescooperating with said sockets to hold them in cocked position with thefuses out of contact :with said jaws; triggers operatively connected tothe latches and arranged to be actuated by adjacent fuse units when theyare blown to trip the latches in succession beginning with any fuse unitof the group which may be initially closed, the trigger of the thirdfuse socket being operatively connected to the latch for the first fusesocket; and spring tensioned striker members for said triggers mountedon said fuse units each secured to afuse element and supported -tos'wing outwardly against the respective triggers to trip them and ejectthe fuse elements.

10. In a fuse replacer of the character described, a metal bracket; aplurality of adjacent sockets pivotally mounted on the bracket;elongated fuse units removablymounted in said sockets; a bracket havinga pluralityof adjacent jaws for said fuse units; means normally biasingsaid sockets to swing the fuse units to their circuit closing position;latch and trip means associated with said sockets automatically to lockthem in open position as they are swung on their pivots and adapted tobe operated in succession as the fuse units are blown; and springtensioned striker members associated with each of said fuse units andadapted to be released when the fuse element is 'blown and thereby tripthe latch means for an adjacent socket whereby the fuse units aretripped in succession.

11. In an automatic fuse replacer of the character described, a bracket;a plurality of open.

ended cylindrical sockets pivotally mounted adjacent to one end on saidbracket and each having an elongated slot throughout its length;expulsion fuse units mounted in said sockets; jaws for said fuse units;means normally biasing said fuse .units to circuit closing position;latch and trip means associated'with said sockets adapted to lock themin open position as they are swung on their pivots; trigger membersassociated with having striker elements arranged behind each of saidsockets and presenting narrow neck portions adapted to guide the unitsinto their proper positions through said slots whereby the hammermembers are positioned to strike the respective trip members for thelatches.

12. In an automatic fuse replacer of the character described, aplurality of pivotally mounted fuse units each normally biased to swingtoward its circuit closing position; latch and trip means associatedwith said fuse units connected to be operated in succession as the fuseunits are blown; and a dashpot connected to at least one of said fuseunitsto delay the closing movement thereof.

13. In an automatic fuse replacer of the character described, aplurality of pivotally mounted fuse units each normally biased to swingtoward its circuit closing position; latch and trip means associatedwith said fuse units connected to be operated in succession as the fuseunits are blown; and adjustable time delay means for one of said fuseunits including a pivotally mounted dashpot having a piston connected toretard the closing movement of the fuse unit.

14. In a fuse replacer of the character described, a bracket; three fusesockets pivotally mounted on the bracket; elongated fuse units mountedin said sockets; Jaws for said fuse units; springs normally biasing saidsockets to swing the fuse units to circuit closing position; latch andtrip means arranged to hold the sockets in cocked position with the fuseunits swung out of their circult closing positions; spring tensionedstriker members for said trip means associated with each of said fuseunits and adapted to trip the latches of the fuse sockets in succession;a dashpot of the leakage and by-pass type associated with one of saidfuse sockets having an adjustable piston rod to vary the time delay inclosing the connected fuse unit.

15. In a fuse replacer of the character described, an active fuse unit;a spring biased fuse unit; means to latch the spring biased fuse unit inits open position; trip means for said biased fuse unit adapted to beactuated to release said unit when the active fuse unit is blown; fluidcontrolled time delay means removably connected to the biased fuse unit;and means whereby the time delay may be varied.

16. In a fuse replacer of the character described, an active fuse unit;a spring biased fuse unit; means to latch the spring biased fuse unit inits open position; trip means for said biased fuse unit adapted to beactuated to release said unit when the active fuse unit is blown; adashpot of the leakage and by-pass type having a piston connected tosaid biased fuse unit; and means to adjust the position of the piston tovary the time delay in closing said fuse unit.

TOM'LINSON FORT JOHNSON.

